policiclizzazioni di enini ed enalleni promosse dalla luce visibile

Simple, linear enynes and enallenes can be readily converted into complex high value-added scaffolds using visible light and suitable Ir(III) complexes as catalyst. 3.0.1 units tethered to a cyclopropyl ring can be obtained through combination of 1,6 enynes and alkenes using an original sequence of photosensitization and photooxidation. Two complementary pathways for the preparation of 3.2.0 bicyclic units were developed from enallenes. 1,7 enallenes afforded target products in high yield with stereo and regiochemical control. Using 1,6 enallenes the cyclization was accompanied by a formal 1,3 sigmatropic rearrangement that delivered 3.2.0 bicyclic imines with a tetrasubstituted headbridge carbon. Finally, the first reported activation of cumulated double bond via energy transfer delivered two families of high complex dimeric structures from 1,6 cinnamoyl allenamides.